This invention relates to devices for drainage of condensate from steam systems, and more particularly, to orifice-type condensate drainage devices.
In typical steam piping systems, devices are provided for drainage of condensate which accumulates in the steam line. Older equipment, such as the widely employed inverted bucket condensate trap, has increasingly been replaced with more simplified orifice devices described, for example, in U.S. Pat. No. 4,426,213, which is incorporated herein by reference. In such orifice devices, the condensate obstructs the passage of steam through the orifice in order to minimize steam loss while permitting drainage of the condensate.
Variation in the pressure and volumetric capacity of the steam and condensate in different steam systems has generally been accommodated by varying the size of the orifice to provide the required flow constriction for proper condensate drainage. In systems requiring small condensate drainage capacity or in systems requiring high pressure steam, drainage devices which have very small orifice diameter, as small as 0.02 inch, have been employed to limit the steam losses. However, the small orifices are susceptible to plugging caused by deposits of calcium carbonate, copper, and oxides of copper which often are entrained in the mixture of steam and condensate.
British Pat. No. 432,033 describes a "steam trap" device for drainage of condensate in which a plurality of condensate drainage nozzles, having "channels", provided with expansion chambers within the nozzles are connected in series and in parallel within cylindrical tubes formed within a housing. The system of channels is described as automatically providing variable flow capacity to accommodate fluctuations in the quantity of condensate to be drained, while limiting the escape of steam. The small expansion chambers within the drainage nozzles are not exposed to the atmosphere and do not provide cooling from the exterior of the housing.